Because there aren't many FT thru-hikers each year, businesses along the trail have yet to adapt to their needs and as a result, resupplying fuel can be frustrating, but only if you are limited to white gas (aka Coleman fuel) or canister fuels. Along the Appalachian Trail hikers can buy white gas and denatured alcohol by the ounce, but not on the FT. Similarly, stores near the FT may stock large butane canisters for RVs and car-camping grills, but not 4oz isobutane fuel canisters for Jetboil, Snow Peak GigaPower, MSR Reactor, or MSR Pocket Rocket stoves.
If you use an alcohol stove, you should have no problem resupplying fuel regularly. While trailside businesses do not sell denatured alcohol or white gas by the ounce, we have found convenience
stores consistently carry isopropyl rubbing alcohol in concentrations strong enough to ignite (70-90% rather than the watered-down 10-20%).
On the PCT, some alcohol stove users have been using a gas-line antifreeze called HEET. Found in gas stations, it burns because it contains methanol, but HEET also contains Xylene and secret proprietary compounds. For environmental and health reasons we strongly discourage the use of HEET. First, you will inevitably spill fuel and you should not be pouring antifreeze into the environment. Additionally, fumes from alcohol stoves enter your food, and who knows what horrible compounds are released from the burning of anti-freeze (a check of its material safety datasheet provided no answers). Our town guide does not include locations where you can find HEET.
For those who use a Jetboil, MSR Pocket Rocket, Snow Peak GigaPower, or some other canister stove, resupplying fuel is difficult on the Florida Trail. Stores in trail towns do not carry
canisters. The best option for resupplying canisters is to ship it them maildrops.
Mailing fuel cans means having a potentially frustrating experience at the post office. Walk into any post office and you are likely to see the poster on the right. According to it, fuel canisters are prohibited in the mail—it’s clear as day right there in the picture.
However, according to USPS regulations posted on the USPS website, you can ship backpacking fuel canisters and non-pressurized liquid fuel if the package is marked “ORM-D” and/or “Surface Delivery Only."
“ORM” stands for Other Regulated Materials. The following two USPS documents are relevant to backpackers trying to ship fuel to themselves. Both documents contain the same information.
1) DMM 601: Mailability
2) Publication 52, Section 342.22a-c
It is a good idea to print out Publication 52 Section 342.22a-c (or keep the PDF on your phone) and bring it with you to the post office in order to trounce stubborn post masters who are unfamiliar with ORM-D guidelines and tell you “no” without double checking the regulations first. Expect at least some clerks at post offices to be unfamiliar with them. In my experience it has been about 50/50.
You may ship more than one canister in the same package. There is no additional paperwork and there are no fees associated with shipping fuel. You also do not need to keep the box open and show the post master the contents of your package. Simply declare the contents of the package and they will write "Surface Mail Only" on the same side of the box as the address. That’s all there is to it.
Here are the relevant excerpts that pertain to isobutane fuel canisters from USPS's Basic Standards for All Mailing Services:
10.12 Gases (Hazard Class 2)
Hazard class 2 consists of three divisions:
a. Division 2.1, Flammable Gases. A material that is a gas at 68°F (20°C) or less and 14.7 psi (101.3 kPa) of pressure. Flammable gases also include materials that have a boiling point of 68°F (20°C) or less at 14.7 psi (101.3 kPa) and that are ignitable at 14.7 psi (101.3 kPa) when in a mixture of 13% or less by volume with air or that have a flammable range at 14.7 psi (101.3 kPa) with air of at least 12% regardless of the lower limit. These conditions must be established in accordance with ASTM E681-85, Standard Test Method for Concentration Limits of Flammability of Chemicals, or other approved equivalent method. The flammability of aerosols must be determined using the tests specified in 49 CFR 173.306(i).
b. Division 2.2, Nonflammable, Nontoxic Gases. A material that does not meet the definition of Division 2.1 or 2.3 and exerts in its packaging an absolute pressure of 40.6 psi (280 kPa) or greater at 68°F (20°C).
c. Division 2.3, Toxic Gases. A material that is poisonous by inhalation and is a gas at 68°F (20°C) or less and a pressure of 14.7 psi (101.3 kPa) or a material that has a boiling point of 68°F (20°C) or less at 14.7 psi (101.3 kPa).
Gases are prohibited in international mail. Toxic gases in Division 2.3 are prohibited in domestic mail. Flammable gases in Division 2.1 are prohibited in domestic mail via air transportation but are permitted via surface transportation if the material can qualify as an ORM-D material (or effective. January 1, 2021, as a consumer commodity material) and meet the standards in 10.12.3 and 10.12.4. Mailable nonflammable gases in Division 2.2 are generally permitted in the domestic mail via air or surface transportation if the material can qualify as an ORM-D material when intended for surface transportation, or as a consumer commodity material when intended for air transportation, and also meet the standards in 10.12.3 and 10.12.4.
An other-than-metal primary receptacle containing a mailable gas may be acceptable if the water capacity of the primary receptacle is 4 fluid ounces (7.22 cubic inches) or less per mailpiece and the primary receptacle meets 49 CFR requirements. Mailable nonflammable and flammable compressed gases are acceptable in metal primary receptacles that have a water capacity up to 33.8 fluid ounces (1 liter or 61.0 cubic inches), depending on their internal pressure. A DOT 2P container must be used as the primary receptacle if the internal pressure is from 140 to 160 psi at 130°F (55°C). A DOT 2Q container must be used as the primary receptacle if the pressure is from 161 to 180 psi at 130°F (55°C). A container with an internal pressure over 180 psi at 130°F (55°C) is prohibited from mailing. Mailable flammable compressed gases are restricted to 33.8 fluid ounces (1 liter) per mailpiece. Mailable nonflammable compressed gases are permitted in individual 33.8 fluid ounce (1 liter) containers that must be securely packed within an outer shipping container. Each mailpiece must not exceed a total weight of 25 pounds.
For surface transportation, packages of mailable gases must be plainly and durably marked on the address side with “Surface Only” or “Surface Mail Only,” and “ORM-D” (or with a DOT square-on-point marking under 10.81.) immediately following or below the proper shipping name (consumer commodity). For air transportation, packages must bear the DOT square-onpoint marking including the symbol “Y,” an approved DOT Class 9 hazardous material warning label, Identification Number “ID8000,” and proper shipping name “Consumer Commodity.” Mailpieces must also bear a shipper's declaration for dangerous goods.